AbstractOne of the main reasons why back-contact (PUM) cells stay somewhat behind in efficiency is because of their lower shunt resistance. A simple method was developed to determine the shunt resistance of the individual process-induced shunt paths. These contributions have led to an electrical model describing the process-induced shunt paths. Individual shunt paths were analysed in detail. Changes in processing were introduced to eliminate the shunting problems. These changes resulted in the shunt resistances beyond 5 kcm2 on 225 cm2 cells with industrial processing.